TL;DR Nezuko is unable to talk because quiet fosters spiritual development, self-control, and inner tranquility. She has been spiritually trained during the course of the show. Demons do regress cognitively after the initial metamorphosis, however once through that stage, they are able to preserve their memories. This means that she must have some sort of memory retention system in place despite her apparent lack of brain activity.
TL;DR Nezuko can’t speak because silence creates spiritual growth, self-control, and inner peace. She has been spiritually training throughout the show so far. Related: I really want Nezuko to give Kanao headpats. I’m looking forward to seeing if this happens in the manga, which I’m just starting.
Will Nezuko turn human?
Yes, she does. Right before Tanjiro temporarily becomes a Demon, they are able to turn Nezuko back into a human again, and it is also through her actions as a human (and Kanao’s as well) that they are able to turn Tanjiro back into his ordinary self.
After turning into a demon, Nezuko still contains her human consciousness while in her demonic state. Other demons that she and Tanjiro have encountered noticed that Nezuko is different from their kind. Instead of relying on human blood to survive, she uses sleep to revitalize her energy.
The answer is YES! Nezuko will turn back to human thanks to Tamayo’s medicine. Tamayo is a demon who devoted her life to researching demons and demon transformations. After she met Nezuko and Tanjiro, she promised the siblings that she will find a cure as long as Tanjiro provides her the blood of the 12 strongest demons under Muzan.
Why is Nezuko so powerful?
Miraculously, Nezuko never devoured a human and went on to accompany her brother on his quest to find a cure for her and slay Muzan Kibutsuji. Because Nezuko was injected very large amount of Muzan Kibutsuji’s Demon blood, she is extraordinarily powerful for a fledging Demon.
Does Nezuko become a demon slayer?
So that’s the answer. Nezuko does become a demon slayer, as recognized by Rengoku. Although it takes a little more time for any other Hashira to give her that respect.
What we know is that he was once a sickly, weak human at some point and he was turned into a Demon around 1700’s by some Doctor, he killed the doctor not knowing that the doctor medication was working and the doctor was working on a cure for his day light problems Ohh and he was the first demon by the way 5K views View upvotes View 1 share.
One way to think about this is nezuko became a demon after Muzan Kibutsuji attacked her family. She is a demon and the younger sister of Tanjiro Kamado and one of the two remaining members of the Kamado family. Nezuko turned into a demon. She was turned into a demon when Muzan Kibutsuji murdered all her.
Thus, Muzan created demons for hundreds of years even when he didn’t want to turn someone. Since he didn’t know anything about the Blue Spider Lily medicine, he needed others to find the plant for him by happenstance. This is the general reason why Muzan turned Nezuko into a demon.
~ Nezuko spurring Tanjiro on. Nezuko Kamado (竈門 禰豆子) is the deuteragonist and main female character of the 2016-2020 fantasy horror manga (and anime) series Demon Slayer: Kimetsu no Yaiba and its stage adaption.